Hydraulic ram



United States Patent HYDRAULIC RAM Ernest C. Chasser, Warren, Ohio, assignor to The Akron Gear and Engineering Company, Akron, Ohio, a corporation of Ohio Application March 12, 1956, Serial No. 570,867

6 Claims. (Cl. 121-46) This invention relates to the art of hydraulic ram equipment, and in particular has reference to hydraulic ram equipment having improved safety means for limiting the extent of pressure occurring interiorly of the ram.

While hydraulic rams have been used for several years past in creating a concentrated degree of pressure in a relatively small area, such rams have been deficient, in view of the fact that no satisfactory means have been developed to limit the amount of hydraulic pressure that can be created interiorly of the same.

Attempts at controlling this internal pressure in the past have been directed primarily to the control of the pressure in the supply line, with the thought being that if the pressure in the supply line is sufliciently low the internal pressure will similarly be low enough to insure safe operation of the device.

Such devices of this general class have not been satisfactory, in View of the fact that the interior volume of an hydraulic ram is constantly changing, with the result that different internal. pressures are required at dilferent times to produce an equal ram pressure exteriorly of the device.

In devices not equipped with control means of any kind, it has been found that upon sufficient building up of internal pressure that the ram cap or cover plate will blow off, with the result that a new plunger mechanism must be inserted at considerable cost to the user.

It has been found that if an automatic bleed-off mechanism is provided for coaction with the telescoping parts of the ram upon extending axial movement thereof, that the internal pressure will be automatically relieved upon the telescoped parts being axially extended to a certain point.

It accordingly becomes a principal object of this invention to provide an automatic ram of the plunger type that is. equipped with a blow-off device for automatically relieving the internal pressure of the ram upon axial extension of the plunger beyond a certain point.

It is a further object of this invention to provide a pressure relieving means that can be easily andquickly secured with respect to existing hydraulic rams of the plunger type.

These and other objects of the invention will .become more apparent upon a reading of the following brief specification, considered and interpreted in the light of the accompanying drawings.

Of the drawings:

Figure l is a vertical section of the improved ram in the closed or inoperative position.

Figure 2 is a similar view but showing the plunger extending to its maximum point.

Figure 3 is an enlarged section showing the improved pressure relieving means of the invention.

Referring now to the drawings and in particular to Figures 1 and 2 thereof, the improved ram, generally indicated by the numeral 10, is shown defined by telescoped hollow cylinders 11 and 12, with the outer cylinder 11 2 being closed at its lower end by base plate 13 while the inner cylinder 12 has a closed upper end thereof that is generally indicated by the numeral 14. In this manner, the cylinders 11 and 12 may move axially of each other, with their axial ends being urged apart under pressure upon entrance of pressurized fluid through conduit 15, with handle 16 providing portability to the ram 10.

Considering first the outer cylinder 11, it will be seen from Figures 1 and 2 that the same has the internal surface 20 that is undercut as at 21 to provide a seat for a sealing member indicated generally by the numeral 22. Additionally, the undercut portion 21 is further provided with radial grooves 23 and 24, within which may be received an O-ring 25 and a metal ring 26, with O-ring 25 serving as a sealing point while the ring 26 retains the sealing member 22 in place against shoulder 21w. In addition to the aforementioned construction, the cylindrical member 11 further includes axially spaced apertures 27 and 28, with aperture 27 threadingly receiving conduit 16, while aperture 28 serves as a port for fluid being ejected when the component parts are positioned as shown in Figure 2, as will be presently described. A baffle plate 29 prevents direct ejection of fluid from port 28.

T nrning next to the construction of the inner cylindrical member 12, it will be seen that the same has the outer surface 30 thereof undercut as at 31 adjacent the open end portion so as to define a shoulder 32 against which may be received sealing means indicated generally by the numeral 33, with ring 34 retaining the sealing means 33 in place against the shoulder 32. The opposed closed end 35 of cylinder 12 is shown provided with a central opening 36, within which may be received a bolt 37, for purposes to be described. Similarly, the closed end 35 is provided with tapered apertures 38, 38 for reception of additional bolts 39, 39 which are employed for retaining a cap 40 with respect to the closed end portion 35.

The improved pressure relieving means, generally indicated by the numeral 40 are shown presented inwardly of the open end of the cylinder 12, so that the sealing means 33 are interposed between the pressure relieving means 40 and the open end of cylinder 12. The pressure relieving means 40 per se are defined by a counterbored aperture 41 (see Figure 3), that has a reduced external opening 42 against which a ball 43 may seat when acted upon by a spring 44 that is placed under tension as a result of being abutted against a plate 45 which is secured with respect to the cylinder 12 in known manner, as by press fitting the same in place. As will best be seen from Figure'3, the ball 43 is normally retained in the fullline position shown in Figure 3, as a result of the action of the spring 44. However, when external force is applied to the exposed surface of the ball 43, it is to be understood that the same will move towards the chain-dotted line position of' Figure 3, as will presently be described. In addition to the aforementioned component parts, the cylinder 12 may be provided with threaded aperture 46, within which may be received a plug 47, the purpose of aperture 46 being to permit counter-boring of the aperture 41 in known manner.

In order that the cylinders 11 and 12 will normally assume the position of Figure 1, the same are shown acted upon by an internal spring 50; the arrangement being such that one end of the spring 50 is fixed with respect to bolt 37 by plug 51, while the other end of the spring 50 is secured with respect to the outer cylinder 11, as a result of bolt 52 and plug 53 being secured to base plate 13.

Turning, next to the construction of the sealing memhers 22 and 33, it will first be seen that the upper sealing member 22 includes a gland Ting 57 that is provided with an internal groove within which may be received an O- ring 58. This gland ring 57sea'ts upon metallic ring 60 that serves as a trip mechanism for the pressure relieving device 40 as will be presently described. By like token, the lower sealing means 33 (Figures 1 and 2) includes a metallic ring 61 which coacts with previously described ring 34 to retain a pedestal ring 62, a filler ring 63 and a U-cup 64 in position, as shown in Figures 1 and 2 of the drawings.

In use or operation of the improved hydraulic ram, it will first be assumed that the component parts have been machined to the condition shown in the drawings and that the component parts are positioned as shown in Figure 1. At this point, the entrance of pressurized fluid along the direction indicated by the arrow in Figure 1 will cause the inner cylinder 12 to move upwardly against the force afforded by the spring 50, with such upward movement being initiated as a result of pressure application against the U-cup 64. After the pedestal ring 62 has cleared the opening 27, pressurized fluid will flow directly into the interior of the cylinder 12 and will exert an auxiliary force against the surfaces 35a that is provided at the closed end 35 thereof. The provision of additional pressurized fluid through conduit 15 will result in the cylinder 12 being extended towards the position of Figure 2; it being understood that during such axial shifting of the component parts the ball 43 will be in the full line position of Figure 3, so that fluid cannot escape from the interior of the cylinder 12.

Upon continuation of this extending axial movement, the exposed surface of the ball 43 will strike the trip ring 60, with the result that the same (ball 43) will be pushed inwardly towards the chain-dotted line position of Figure 3. At this time pressurized fluid may escape from the interior of the cylinder 12 through the opening created between the ball 43 and the reduced diameter opening 42. Such fluid will flow into an annular chamber 100 (Figure 2) that is defined by the rings 60 and 61, together with the external surface of cylinder 12 and the internal surface 20 of cylinder 11. This annular chamber 100 communicates with port 28, with the result that pressurized fluid entering the chamber 100 will be immediately ejected exteriorly of the device 10 through the port 28. Because of the high pressure of such fluid being ejected the baffle plate 29 is positioned so as to deflect this fluid downwardly along the exterior surface of cylinder 11.

It is believed apparent that as long as the device is in the extended position of Figure 2 that further axial extending movement of the cylinders 11 and 12 will be impossible, due to the fact that the pressure interiorly of the ram 10 is being continuously relieved as a result of ball 43 being in the chain-dotted line position as previously described.

When the pressure application by the ram is completed, the pressure in line 16 will be relieved, at which time fluid will be forced outwardly thereof as a result of the contracting force offered by the spring which will gradually return the component parts to the position of Figure 1 of the drawings.

It will 'be seen from the foregoing that there has been provided a new and novel type of hydraulic ram mechanism that is characterized by the presence of internal pressure relieving means that continuously function after a certain point of axial extension has been obtained. It will be seen that even if additional pressure is applied through the inlet port of the ram the internal pressure will not appreciably increase, due to the fact that this internal pressure i being constantly relieved as long as the cylinders 11 and 12 are in the extended condition of Figure 2. i While a concise and specific recitation of the construction has been set forth in the preceding paragraphs in accordance with the requirements of the patent statutes, it is to be understood that the invention is not to be so limited. Accordingly, modifications of the invention may be resorted to without departing from the spirit hereof or the scope of the appended claims.

What is claimed is:

l. A hydraulic rarn of the character described, comprising; a hollow cylinder closed at one end and having an inlet port adjacent thereto; a hollow cylindrical plunger of elongate configuration telescopically received in said cylinder and having a closed axial end, whereby said plunger and said cylinder define an axially expandable fluid chamber; axially spaced sealing means respectively carried by said plunger and said cylinder at the open ends thereof and respectively engaging said cylinder and said plunger in sealing contact therewith; a second fluid port provided in the wall of said cylinder adjacent said open end thereof; a normally closed fluid port extending radially through the cylindrical side wall of said plunger at an axial location falling between said sealing means of said plunger and said closed end thereof; and means for opening said normally closed port upon movement of said plunger to the point where said second port and said normally closed port are in substantial alignment with each other; whereby said axially expandable fluid chamber is relieved at an axial location between its closed ends upon opening of said normally closed port opening.

2. A hydraulic ram of the character described, comprising; a hollow cylinder closed at one end and having an inlet port adjacent thereto; a hollow cylindrical plunger of elongate configuration telescopically received in said cylinder and having a closed axial end, whereby said plunger and said cylinder define an axially expandable fluid chamber; axially spaced sealing means respectively carried by said plunger and said cylinder at the open ends thereof and respectively engaging said cylinder and said plunger in sealing contact therewith; a second fluid port provided in the wall of said cylinder adjacent said open end thereof; a normally closed fluid port extending radially through the cylindrical side wall of said plunger at an axial location falling between said sealing means of said plunger and said closed end thereof; and means for opening said normally closed port upon movement of said plunger to the point where said second port and said normally closed port are in substantial alignment with each other; whereby said axially expandable fluid chamber is relieved at an axial location between its closed ends upon opening of said normally closed port opening; said last-mentioned means including a shiftable plug normally blocking said normally closed port and projecting radially beyond said plunger under tension, and a trip ring carried by said cylinder and being engageable with said exposed surface of said plug upon relative axial movement between said cylinder and said plunger, whereby said plug may be moved radially inwardly of said plunger upon contact with said ring, whereby said normally closed port is opened.

3. A hydraulic ram of the character described, comprising; a hollow cylinder closed at one end and having an inlet port adjacent thereto; a hollow cylindrical plunger of elongate configuration telescopically received in said cylinder and having a closed axial end, whereby said plunger and said cylinder define an axially expandable fluid chamber; axially spaced sealing means respectively carried by said plunger and said cylinder at the open ends thereof and respectively engaging said cylinder and said plunger in sealing contact therewith; a second fluid port provided in the wall of said cylinder adjacent said open end thereof; a normally closed fluid port extending radially through the cylindrical side wall of said plunger at an axial location falling between said sealing means of said plunger and said closed end thereof; and means for opening said normally closed port upon movement of said plunger to the point where said second port and said normally closed port are in substantial alignment with each other; whereby said axially expandable fluid chamber is relieved at an axial location between its closed ends upon opening of said normally closed port opening; said normally closed port including an aperture and a ball tensionally urged against the exterior opening thereof to block the same; said ball having a portion thereof projecting with respect to the exterior of said plunger.

4. A hydraulic ram of the character described, comprising; a hollow cylinder closed at one end and having an inlet port adjacent thereto; a hollow cylindrical plunger of elongate configuration telescopically received in said cylinder and having a closed axial end, whereby said plunger and said cylinder define an axially expandable fluid chamber; axially spaced sealing means respectively carried by said plunger and said cylinder at the open ends thereof and respectively engaging said cylinder and said plunger in sealing contact therewith; a second fluid port provided in the Wall of said cylinder adjacent said open end thereof; a normally closed fluid port extending radially through the cylindrical side wall of said plunger at an axial location falling between said sealing means of said plunger and said closed end thereof; and means for opening said normally closed port upon movement of said plunger to the point where said second port and said normally closed port are in substantial alignment with each other; whereby said axially expandable fluid chamber is relieved at an axial location between its closed ends upon opening of said normally closed port opening; said normally closed port including an aperture and a ball tensionally urged against the exterior opening thereof to block the same; said ball having a portion thereof projecting with respect to the exterior of said plunger; said last-mentioned means including a trip ring carried on the internal surface of said cylinder and being engageable with the projecting portion of said ball upon relative axial movement between said cylinder and said port.

5. The device of claim 4 further characterized by the presence of a baflie deflector secured to the external surface of said cylinder and covering said second port thereof.

6. The device of claim 4 further characterized by the fact that said closed ends of said cylinder and said plunger are connected by a tension spring, whereby the same are urged towards each other.

References Cited in the file of this patent UNITED STATES PATENTS 1,244,317 Gaffney Oct. 23, 1917 1,685,697 Guerin Sept. 25, 1928 1,713,906 Lake May 21, 1929 2,085,111 McConnell June 29, 1937 2,211,479 Pomeroy Aug. 13, 1940 

